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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
TK locus
Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Metabolic activation system:
cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with Aroclor 1254 (500 mg/kg bw)
Test concentrations with justification for top dose:
First experiment:
with and without metabolic activation: 625, 1250, 2500, 3600 and 5000 µg/mL

Second experiment:
without metabolic activation: 313, 625, 1250, 2500 and 3600 µg/mL
with metabolic activation: 156, 313, 625, 1250, 2500 and 3600 µg/mL

Repeat of second test:
without metabolic activation: 2.5, 5, 10, 20, 40, 80, 160 and 320 µg/mL
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-ethyl-N-nitrosourea (50 µg/mL, -S9), 7,12-dimethyl-1,2-benzanthracene (3.3 µg/mL, +S9)
Evaluation criteria:
The test item was considered as mutagenic when all of the following criteria were met:
- increases in the mutation frequency were observed in treated cultures compared to the corresponding negative control values at one or more test concentrations
- the increases showed a dose-response relationship
- the increases were reproducible between the replicates and the first and second test (when treatment conditions were the same)
- the increases were statistically significant
- the increases exceeded the historical negative control range
- the relative survival of the test groups was at least 15% at the end of the treatment period

When the above mentioned criteria were not met, the test item was considered as non-mutagenic.
Statistics:
Single values of the duplicates were determined from the examined parameters. Statistical analyses were performed with the SAS (R) procedures version 8.1 (SAS Institute Inc., Cary, North Carolina 27513, USA). In detail, mutation frequencies of treated samples were compared to the correpsonding negative controls with the analyis of variance test.

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
without S9: starting from 3600 µg/mL (first test (4 h exposure)) and 160 µg/mL (second test (24 h exposure)), with S9: starting from 2500 µg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative